The first presentation on 24th September
2009 was held jointly with the Welding and Joining Society and proved to be very popular with 83 attendees. Stig Wästberg presentation of “HISC- Design Criteria Based on Testing and Experience” considered duplex and super-duplex stainless steels in subsea equipment. Although the general experience with these materials is good, significant failures have occurred due to Hydrogen Induced Stress Cracking (HISC). The conditions necessary to cause HISC, failure characteristics and the research effort that has been performed by DNV was presented with an outline of the recently updated (October 2008) DNV-RP-F112 “Design of Duplex Stainless Steel Subsea Equipment Exposed to Cathodic Protection”.

“Application of Erosion Modelling was presented by Frances Blackburn to an audience of 36 on 27th October 2009. Her presentation detailed some of the erosion models that are widely available and how they have been applied to ConocoPhillips UK North Sea assets to manage integrity. ConocoPhillips’ approach to erosion modelling in their UK North Sea assets was described highlighting the importance of understanding the limitations of erosion models used, input data available and the interpretation of acoustic monitoring, intrusive ER probes, UT inspection, choke settings and flow rates. A significant discussion of industry wide experiences of the application erosion modelling was held after the presentation by the branch members.

Further interest was generated by “Superduplex Stainless Steel – A Cost Effective Option for Subsea Applications” presented by Roger Francis of RA Materials on 24th November 2009 with 44 people attending. Roger has over 30 years experience as a corrosion engineer and was Chairman of NACE Europe from 2003 – 2007 and is presently serving as a Director of NACE International for a second term (2007- 2010). He sits on the EFC (European Federation of Corrosion) Working Parties on Marine Corrosion and Corrosion in the Oil and Gas Industry. His presentation considered the high strength alloys used for forgings in wellheads, such as superduplex stainless steel and he presented data gathered for Zeron 100 51/8”, 10,000lb forgings produced using a new forging route. His results showed the higher levels of toughness achievable down to -70°C for a range of casts and heats and constant load hydrogen embrittlement tests showed the much higher threshold stress for crack initiation compared with conventionally made forgings. The new route enables the continued use of superduplex stainless steel under the more severe operating conditions of current wells.

“Life Extension of Existing Assets from a Cathodic Protection Perspective” was presented to 57 attendees at the ICorr Aberdeen branch meeting on 26th January by Jim Britton of Deepwater. His talk described the design rationale and basic installation history of four recent offshore/ marine impressed current cathodic protection (ICCP) replacement projects. These included applications to a SPAR Structure in >600 meters of water in the Gulf of Mexico, a European Wind farm in <6 meters of water, a two similar fixed platform structure in 180 meters(One in Gulf of Mexico, One in South China Sea) and a large dock complex in the Canadian Arctic. Each of the four projects had unique problems to overcome, and employed a range of different ICCP approaches. Design rationale and system performance will be addressed along with a basic installation case history of each project.

Material & Chemical Selection & Ongoing Corrosion Management Issues for Bundled Pipeline Systems Parallel was presented by Dr. Steve Turgoose to 51 attendees. Multiple production pipeline systems can suffer from some quite unique corrosion problems. Whilst the internal degradation mechanisms are the same as any producing system, the difference with multiple pipeline systems relates to the variable flow down different lines and the effect this has on water cut, corrosivity and dosed chemical levels. Some examples of Intertek-CAPCIS experience with various issues surrounding corrosion and integrity of parallel production pipelines were presented. These highlighted some major issues along with the methods used to understand, control and manage the degradation.

Members Area

Institute Technical Forum